PVA as a sealer - drying time on plywood?

Jon Parker

unread,

May 28, 2015, 1:02:07 PM5/28/15

to

Folks,

Rebuilding a caravan, rain due tomorrow, must finish get window seals on tonight as nowhere to store it undercover.

On 3.6mm bare ply which I have coated with a 50/50 mix of PVA and water, how long before I can paint that plywood please?

Thanks
JP

stuart noble

unread,

May 28, 2015, 1:46:06 PM5/28/15

to

If using a water based paint, as soon as is the pva is touch dry. For a
solvent based paint it needs to be bone dry

Phil L

unread,

May 28, 2015, 2:18:53 PM5/28/15

to

"Jon Parker" <jonbo...@googlemail.com> wrote in message
news:7ee2c983-75ea-48d4...@googlegroups.com...

What was the point of 'sealing' the plywood? - to prevent the paint from
soaking in perhaps?

harryagain

unread,

May 28, 2015, 2:23:28 PM5/28/15

to

"Jon Parker" <jonbo...@googlemail.com> wrote in message
news:7ee2c983-75ea-48d4...@googlegroups.com...

Paint on PVA sealed surfaces often fails to adhere well.
Doesn't "key" to the smooth impervous surface.

stuart noble

unread,

May 29, 2015, 2:49:36 AM5/29/15

to

"Keys" to glass well enough :-)

Cursitor Doom

unread,

May 29, 2015, 3:23:03 PM5/29/15

to

On Thu, 28 May 2015 19:21:00 +0100, Phil L wrote:

> What was the point of 'sealing' the plywood? - to prevent the paint from
> soaking in perhaps?

The pain manufacturers commonly recommend doing so, presumably for that
reason. I use PVA neat, though.

tabb...@gmail.com

unread,

May 29, 2015, 3:43:43 PM5/29/15

to

but not to slick pva. Its ok if you don't put too much on, but its easily overdone.

NT

Cursitor Doom

unread,

May 29, 2015, 4:55:46 PM5/29/15

to

There's nothing to stop you scuffing it up a bit with a piece of say 240
grit wet or dry; doesn't take 5 mins/sq mtr.

Phil L

unread,

May 30, 2015, 9:35:30 AM5/30/15

to

"Cursitor Doom" <cu...@notformail.com> wrote in message
news:mkae8a$hb2$1...@dont-email.me...

So instead of painting the wood, you're painting the pva, and if that peels
off, so does the paint.
When I'm painting wood, I use a thinned down undercoat so that it soaks
right in, then build the coats up on top

tabb...@gmail.com

unread,

May 30, 2015, 12:42:31 PM5/30/15

to

Yes there is. PVA on plaster can't be counted on to form a uniform slick, so sanding will break up the plaster surface. And why wuold one create such unnecessary work?

Only in newsgroups & fora do such questions get discussed.

NT

Cursitor Doom

unread,

May 31, 2015, 10:56:00 AM5/31/15

to

Eh?? What's plaster got to do with it? This thread's about PVA on plywood
and that's what my remark was addressing.

Cursitor Doom

unread,

May 31, 2015, 10:58:30 AM5/31/15

to

On Sat, 30 May 2015 14:39:41 +0100, Phil L wrote:

> So instead of painting the wood, you're painting the pva, and if that
> peels off, so does the paint.
> When I'm painting wood, I use a thinned down undercoat so that it soaks
> right in, then build the coats up on top

I should have been a bit more precise. I only use PVA as a foundation for
painting wood which is going into bathrooms and other wet areas.

tabb...@gmail.com

unread,

May 31, 2015, 12:40:33 PM5/31/15

to

When I've used it as a primer its usually been to hold the substrate together, which means plaster.

NT

tabb...@gmail.com

unread,

May 31, 2015, 12:40:51 PM5/31/15

to

it's water soluble

NT

Cursitor Doom

unread,

May 31, 2015, 4:29:21 PM5/31/15

to

As are a lot of modern paints - until they dry out.

Cursitor Doom

unread,

May 31, 2015, 4:31:07 PM5/31/15

to

On Sun, 31 May 2015 09:40:28 -0700, tabbypurr wrote:

> When I've used it as a primer its usually been to hold the substrate
> together, which means plaster.

For applying further plaster, fine. But for painting over raw substrate
I'd sooner use a proper stabilising solution.

tabb...@gmail.com

unread,

Jun 1, 2015, 4:19:55 AM6/1/15

to

how is that better?

NT

Cursitor Doom

unread,

Jun 1, 2015, 7:14:11 AM6/1/15

to

On Mon, 01 Jun 2015 01:19:51 -0700, tabbypurr wrote:

> how is that better?
>
>
> NT

Specifically formulated for such purposes!

stuart noble

unread,

Jun 1, 2015, 8:51:16 AM6/1/15

to

PVA is the basis of many different products, all allegedly specially
formulated. Mostly bollocks I suspect.
I mixed Gyproc joint filler and neat pva to finish off a job at the
weekend because I couldn't be bothered to go out for a single cartridge
of Gripfil.

tabb...@gmail.com

unread,

Jun 1, 2015, 9:21:17 AM6/1/15

to

On Monday, 1 June 2015 12:14:11 UTC+1, Cursitor Doom wrote:
> On Mon, 01 Jun 2015 01:19:51 -0700, tabbypurr wrote:
>
> > how is that better?

> Specifically formulated for such purposes!

that doesn't tell us how its better, or even if its better

NT

Vir Campestris

unread,

Jun 1, 2015, 4:04:40 PM6/1/15

to

On 30/05/2015 14:39, Phil L wrote:
> When I'm painting wood, I use a thinned down undercoat so that it soaks
> right in, then build the coats up on top

Call me old fashioned, but I reckon the first coat should be a primer.
Clue is in the name :P

That said, boatbuilders these days are using a thin epoxy as a first
coat onto wood, it soaks in really well. Must be overcoated though as
it's UV sensitive.

Andy

schet...@gmail.com

unread,

Apr 2, 2017, 6:24:44 AM4/2/17

to

schet...@gmail.com

unread,

Apr 2, 2017, 6:38:06 AM4/2/17

to

A friend said a tip for putting down ply which will get wet (in my case the base of a trailer) is to just seal the edges with PVA. Product advise to seal was with a 1 to 3 mix with water. The edge is quite thirsty and when its done still leaves a roughness for purchase of the paint. I kind of agree about pva on a smoothish surface taking any paint off because the paint may not penetrate the pva'd surface - a thinned coat of paint on the untreated ply seems to the best way to get subsequent paint to adhere.